1. Field of the Invention
The present invention relates to an apparatus which performs both mathematical calculations and postal zip code-to-postal zone conversions. This apparatus may be used by individuals or commercial users to make mailing parcels and priority mail easier.
The United States Postal Service has established a system for numerically identifying each postal delivery area in the country. Known as the Zone Improvement Plan (ZIP), the system assigns a five digit number (the zip code) to each post office in the United States. The first three digits of each zip code designation, called the zip code prefix, identify the sectional center facility of the postal address. The assignment of each zip code to an area is both arbitrary and permanent.
The Postal Service has also established a system of eight zones for calculating the postage required to mail parcels and priority mail from any given location to any other location in the country. The zone system is generally based on the distance between the location from which mail originates to its destination. Therefore, postal zone designations are not merely a function of the destination location but rather are a function of both origination and destination locations. One must know the point from which, for example, a parcel is mailed in order to determine the zone in which its destination falls and, hence, the postage required to mail the parcel.
Since all postal locations have a permanently assigned zip code, the postal destination zone is also a function of the zip codes of the point of origination and destination of applicable mail.
Through extensive publicity for and easily accessible information on the zip code system, the Postal Service has accustomed people to learn or obtain the zip code of the destinations for their mail. However, few people know which zone designates the destination of their mail. Therefore, the Postal Service publishes charts for approximately 600 mail origination locations which show destination zones as a function of the three digit prefix of destination zip codes. Other charts tabulate the postage as a function of different weight-zone combinations. A user must, therefore determine the proper zone for the destination of this parcel from one chart and, after weighing the parcel, determine the proper postage from the other chart.
The present invention makes this postage calculation operation easier and faster.
2. Description of the Prior Art
Postage calculating systems are known. For example, U.S. Pat. No. 3,635,297 (Salava) discloses a computer-type postage calculator in which the prefix of a destination zip code is converted to zone information through the use of a look-up table in which zones are stored as a function of zip code prefixes. The table is scanned in numerically ascending order until a correspondence is found between the destination zip code prefix entered by the user and one of the addresses in the table. Signals representing the parcel weight, destination zone and class of handling are algebraically handled. The computer is supposedly interfaced with a postage meter.
U.S. patent application Ser. No. 715,914 (Check et al.), filed Aug. 19, 1976 and assigned to the assignee of the present invention, discloses a system for automatically setting a postage meter as a function of package weight and destination. The system includes input means for generating weight-representing signals and input means for providing signals representing the destination zip code for the mail. Means for determining the destination zone as a function of the destination zip code using an incremental calculating method as well as means for computing the proper postage as a function of the weight-representing signal and a destination zone signal are incorporated in the system. A meter setting mechanism translates the calculated postage into positions of postage-printing wheels.
Both of the systems described above are best suited for use by those who handle medium to large volumes of mail. Because of their complexity and cost, they are not well suited for use by individuals and small businesses who handle moderate volumes of mail.
Another publication that discloses a device for converting zip code information to zone information is U.S. Pat. No. 3,692,988 (Dlugos et al.), assigned to the assignee of the present invention. The device is used in conjunction with a parcel postage metering system which is the main subject of patent.